The flag was adopted by new Constitution of 13 January 1992. The Constitution come into force on 12 February 1992.
Ratio 1:2 according to Album 2000Željko Heimer, 29 June 2002

The books I have depict the flames in "soyombo" as of almost equal height; a bit like a rose.Peter Hans van den Muijzenberg, 7 July 2002

I noticed yesterday during a televised UN press conference the flag of Mongolia, clearly shown behind. It had the star above the emblem;
like pre-1992 flag. The question is.. has Mongolia reverted to its former design..or is it another UN error?
J.J.Andersson, 2 October 2002

The Constitution of Mongolia was adopted on 13 January 1992 and came
into force on 12 February 1992.

Chapter One. Sovereignty of the State
Article 12
1. The symbols of the independence and sovereignty of Mongolia are the State Emblem, Standard, Flag, Seal and the Anthem.
2. The State Emblem, Standard, Flag and the Anthem shall express the
historical tradition, aspiration, unity, justice and spirit of the
people of Mongolia.
3. The State Emblem shall be based on the white lotus of purity. The outer frame shall be the "Tumen Nusan" of eternity in the shape of a
blue sphere symbolizing the eternal sky. In the centre shall be a combination of the Golden Soyombo and the Treasured Steed, an expression
of the independence, sovereignty and spirit of Mongolia
In the upper part is the Chandmani which grants wishes and symbolizes
the past, present and future.
In the lower part shall be a green background of mountains representing Mother Earth and the Wheel of Destiny. Mixed in with the Wheel of
Destiny shall be a "khadag" - scarf symbolizing welcome.
4. The traditional Great White Standard representing the unified
Mongolian State is a State ceremonial attribute.
5. The State Flag shall be divided vertically into three equal parts
coloured red, blue and red. The three stripes, of identical width, shall
be blue for the eternal sky in the middle, and red, the symbol of progress and prosperity, for the two stripes on either side. The golden
Soyombo shall be depîcted in the centre of the red stripe nearest to the flag pole. The ratio of the width to the length of the Flag shall be 1:2.
6. The State Seal, having a lion-shaped handle, shall be square in form.
It shall have the State Emblem in the centre and the words "Mongol Uls"
[Mongolia] written on both sides. The holder of the State Seal shall be the President.
7. The procedure for the ceremonial use of the State symbols and the text and melody of the State Anthem shall be prescribed by law.

Chapter Three. Structure of the State
Part I. The Legislature
Article 23 [Responsability, Mandate]
...
2. The mandate of a member of the National Parliament begins with an
oath taken before the State Emblem and expires when newly elected
members of the National Parliament are sworn in.

Source: Vagnat & Poels (2000). Constitutions - What they tell us about
national flags and coats of arms.Ivan Sache, 14 September 2003

There is a letter from Mongolian Embassy in London to the Flag
Institute, Jos Poels, that Chris Southworth had access to (and which
he kindly shared with me) and that includes consturction details of
the Mongolain national flag. The letter says that the consturction
sheets (of the flag and the COA) are taken from the 1992 Mongolian
Constitution (is that so? I doubt that a constitution would include
such detailed specifications). beside the flag there is also much
more detailed construction sheet of the national COA (emblem) that is
way to complicated for me right now. Anyway, let's take a look at the
flag.

The entire flag is sized 60x120 units, each
vertical stripe so being 40 units long horizontally.
The yellow emblem is within a virtual rectangle 45x22 units that is
offset to the top - i.e. the distance from the top of the flag to the
top of the flames is 6 units, white the diestance from the bottom of
the yellow emblem to the bottom of the flag is 9 units. The two
vetrical yellow collums are 24x5 units each, the elements between
them are all 10 units long horizontally, one unit between each,
triangle 3 unit high, rectangles 2 unit high and the yin-yang 10
units in diameter. Two dots are 2 units in diameter, 2.35 units from
the top viz. the bottom. The red line dividing two helves is 0.5 unit
wide.
The crescent is composed of two arches of circles, lower 5.5 units in
radius and upper of 6 units, the two centers are vertically distanced
2.5 unit (i.e it makes the crescent 2 unit wide at the bottom). The
sun disk is 4 units in radius, the top to match with the top of the
circle forming the lower arch of the crescent. The flames are formed
of a lower helf circle 2.5 units in radius the central flame reching
5.5 from the center of the lower half circle. The two small circles 1
unit in diameter form the lower gaps between the flames. The
remainder of the wavy form of the flames is not further defined (the
outer flcames seems to reach about 3 units from the center of the
half-circle.
Željko Heimer, 16 July 2003

The English Translation of the document "The State Flag of
Mongolia General requirements (MNS 6262 : 2011)". The information was published
July 8th, 2011 and this standard will become official starting February 22,
2012.

In the term of the construction sheet we have at FOTW
already, the standard pretty much conforms to that except for some small details. They also use the 60x40:40:40 (120)
measurements as was shared at mn.html#sheet. The details that changed was the
Ying-Yang symbol; the main emblem itself is still 1/6 of the length of the flag (so 10 units on a 60 unit flag). Each red eye is still 2 units diameter, but the
circles around it slightly changed. The first larger circle is R=2.35a (where a is 1 or any number you so choose) and the second is now R=2.95a instead of R=2.65.

Another change is the colors used on the flag. Below is the new CMYK values for each part of the flag:

"5.1. Colour requirements
5.1.1 The appearance of the flag shall correspond to picture 1.
5.1.2 The flag shall combine red, blue and red bands.
5.1.3 The middle band of the flag corresponding to the one third of the size of the flag shall be in blue (C 100%, M 60%, Y 000%, K 000%) colour.
5.1.4 The two bands each equal to the one third of the size of the flag shall be in red (C 010%, M 100%, Y 090%, K 000%) colour.
5.1.5 Soyombo that is placed in the middle of the hoist-side red band shall be in golden yellow (C 000%, M 015%, Y 000%, K 000%) colour."

The protocol manual for the London 2012 Olympics (Flags and Anthems Manual London 2012 ) provides recommendations for national
flag designs. Each NOC was sent an image of the flag, including the PMS shades, for their approval by LOCOG. Once this was obtained, LOCOG produced a 60 x 90 cm
version of the flag for further approval. So, while these specs may not be the official, government, version of each flag, they are certainly what the NOC believed
the flag to be.
For Mongolia: PMS 485 red, 2915 blue, 109 yellow. The vertical flag is simply the horizontal version turned 90 degrees clockwise
Ian Sumner, 11 October 2012

I was reading the history of Mongolia tonight, and from what I read it seems that Mongolia gained (or declared) its first independence in 1911, about the same time as Dr Sun Yat-sen led the revolution which overthrew the Ching Dynasty of China. Four years later in 1915, the status was degraded to self-government. And once again in 1921, the status was even withdrawn, under military threat from Chinese troops, to be simply an administrative district.

Nevertheless, with "aid" from "white Russian" troops, Mongolia declared its second independence, but this newly independent country lasted for only five months. It was totally crushed by the Soviet red army, and then the Mongolian state that we know today was set up.Michael Wang, 25 April 1997

Russian general-lieutenant baron Roman Ungern-Sternberg, chief of mongolian cavalry, was in fact the dictator of Mongolia since 1920. On 3, February, 1921 mongolian troops of Ungern-Sternberg occuried the capital of Mongolia (city of Urga). Soon they were banished by communist troops of Sukhe-Bator. On 8, July, 1921 government of Sukhe-Bator went to Urga. Soldiers of Ungern-Sternberg had the yellow banners with 'soyombo' since 1911. These banners were 'semi-national' flags of mongols.Victor Lomantsov, 4 April 2001

I am attempting to find a picture of the Mongolian flag that was
flow with/under Gen. Ungern in 1911-1920. I do know it was a yellow square with
orange border and 3 streamers.Robert Hammond, 21 August 2003

The yellow square with orange border and streamers was used 1911 to
1919. See the World Statesmen website
for graphics.Ned Smith, 22 August 2003

According to Alfred Znamierowski:

The basic design of the flag dates from 1940. In 1992 the star surmonting the emblem was removed and the design of the Soyonbo, an ancient Mongol symbol, was modified.

The blue shade of Mongolian flags is given very differently in various sources,
ranging from a very plae blue to very dark royal blue. I guess that there is no
really regualtions demanding one of the other, and that any blue does the job.Željko Heimer, 29 June 2002

"The soyombo (or soyemba) is the national emblem of Mongolia. Its origins are closely associated with Lamaism, and the various elements of the design were regarded as having mystical meanings. Individually, parts of the design also may be related to brands of ownership placed on horses and cattle. The star at the top of the modern soyombo is a recent addition to the traditional symbol; it represents socialist revolution. Below that, a fire symbol has multiple significance. It represents revival and growth, and also the family hearth and the continuity of the people. The fire has three tongues of flame, symbolizing past, present, and future. Below the fire are symbols of the sun and moon, links to the pre-Buddhist nature religion of the Mongols. In ancient Mongolian symbolism, an arrow or spear pointing to the ground meant death. In the soyombo, two downward-pointing triangles signify death to the enemies of the Mongols. Two horizontal rectangles represent honesty and fairness between rulers and the people. Set between the two horizontal rectangles is the Chinese sign of yin and yang, representing dark and light, fenale and male, cold and hot - the unity of all opposites in the cosmos. In Mongolian symbolism, the figures in the yin-yang circle represent two fish which, because fish never close their eyes, signify reason and wisdom. The two vertical rectangles represent a fortress, recalling the old Mongolian proverb "The friendship of two men is stronger than stone walls." The symbol of the fortress signifies that the unity of
the Mongol people is the foundation of the nation's strength. The soyombo was adopted as the official symbol of the Mongolian People's Republic by the first People's Great Khural in 1924. A golden soyombo is emblazoned on the left panel of Mongolia's blue-and-red national flag."

From: 'The Land and People of Mongolia', by John S. Major, New York, 1990. (p. 183)Jarig Bakker, 12 April 2000

The ornament in the hoist is called the soyonbo, Mongolia's national symbol. In the communist era it was capped by a gold five-pointed star.David Kendall, 11 October 1996

Here the flag of the Mongol Pioneer Organization "Sukhe-Bator". The flag is
red with the logo in center. The logo shows a red star with three flames, in
the center a figure of its naming patron, Damdin Sükhbaatar (Damdin
Sukhe-Bator). The white scroll shows some Mongolian words "Always ready" in
Mongol and in red.
More information about the Sukhe-Bator pioneer organization:
http://en.wikipedia.org/wiki/Sukhe_Bator_Mongolian_Pioneers_Organization"Jens pattke, 1 May 2013

The symbol of the organization is similar to these of the Soviet pioneer/youth
organization, the Komsomol, resp. its organization, the Lenin pioneers.
The symbol shows a star with three flames, in the center a figure of its naming
patron, Damdin Sükhbaatar (D. Sukhe-Bator)
Another part is a scroll which shows some Mongolian words, I assume either
Sukhe-Bator, of the words "Always ready" in Mongol.
The symbol, as shown on some pins:
- http://gmic.co.uk/index.php...49087- http://gmic.co.uk/index.php...64099Dirk Schönberger, 6 January 2013

Mongolian air marking is
yellow bordered red 5 point star
bearing yellow soyonbo (according a real photo of mongolian fighter).
The top of the soyonbo in the air marking
is not a flame but a yellow 5-pointed star and two eyes and center line are not yellow
but black.
Nozomi Kariyasu, 6 December 2003

[cos98] reports that between 1936 and 1992 the mongolian markings were red
stars on wings and red "zoyombo" on the tail. Since 1992, a new roundel is
adopted which is red star bordered in yellow charged with yellow "zoyombo",
Insignia (http://www.insigniamag.com/mong14.html) images from 1993 in which
MiG-21PFM with: "A Red Mongolian Zoyombo insignia is used on the fin sides
only. " and Mil Mi-24 with: "A Yellow Mongolian Zoyombo insignia has been
superimposed over a Soviet Red star. The star is outlined with a Yellow
rule."
See also http://www.geocities.com/sheepo74/mongolia.html.
It is reported (http://www.worldairforces.com/Countries/mongolia/mon.html
and http://www.scramble.nl/mn.htm) that all fighters are frounded and the
only combat planes in use are four Mi-24's. Transport planes are operated by
MIAT under its livery.
Government planes having an emblem on tail and national flag on fusalage.Dov Gutterman, 20 June 2004

I have compared the new [bry85] with the known sources, and here my remark:
Mongolia - a red star in red ring (rays touchung the rings)Dov Gutterman, 6 July 2004

I send you Bogd Khan Kingdom of Mongolia flag. The Kingdom
officially declared its independence in December 29, 1911 from Manchu
Qing Dynasty in China. By the way, it is the last flag that have drawn
soyombo in old religeous colors. Since 1924, standard verion of
soyombo on the flags became "Golden".
Mash O.Sarlagtay, 24 April 2006

by Ben Cahoon

Reconstructed image of the very detailed flag of Mongolia used 1911-1924
made after photo of Mongolia Museum display of historic flags of Mongolia 1911-1992:
https://groups.yahoo.com/...Museum photo varies from flags reported from western sources. My bet is that the early flags were probably not widely used outside government and maybe at the Mongolia embassy in the USSR.
Ben Cahoon, 27 March 2015

by Zeljko Heimer and Eugene Ipavec

Image of Mongolian Independence Bogd Khan Kingdom flag, 1912, made after Nozomi Kariyasu photos made in Mongolian Military Museum in Uran Bator in June 2008.

A flag known to have been used in 1921 was red with a half moon pointed up and a ball above. According to Flaggenmitteilung an Imperial (Hutuktu) flag was in use in 1921 (first time?). This was square yellow, bordered orange, and with three rectangular wings of fabric on the fly side.Jaume Ollé, 23 April 1997

In 1921 Provisional Government of Outer Mongolia adopted the red flag with yellow ball and crescent. We don`t know they were at the centre or they were in canton. We have no images of this flag. We only have reconstruction of the flag (with the figures near the hoist) made in 1920ths.Victor Lomantsov, 4 April 2001

images into the Mongolia folder!

I visited Mongolia two times to research their flags and bought Mongolan flag books at a few museums and book stores.
I could not find several historical flag images already reported from Europe such as mn-1921 red flag with yellow sun and crescent
at canton. ...
It is amazing to me. Mongolian flags design during that time were much more complicated.
Likewise they had national emblems with complicated design than we thought."
Nozomi Kariyasu, March 2015

Photo of Mongolia Museum display of historic flags of Mongolia 1911-1992:
https://groups.yahoo.com/...The Museum photo does not mention the Red/Blue version listed as 1924-40 by FOTW or the reported 1921
"red flag with yellow ball and crescent flag".
Ben Cahoon, 27 March 2015

I wonder what primary documentation exists on this flag? Your message
has led me to wonder if the flag is nothing more than the product of
a comic book artist's imagination (and yes the U might have stood for
Ungern in that case). What was the publication date of that comic,
and are there any reports of the flag which predate that?
On the other hand, if my mild skepticism is misplaced and the flag
actually existed, perhaps the U is just the result of trying to
reconstruct an image from a sketchy verbal description- maybe there
was a yellow or orange flag with a horizontal black crescent such as
the horizontal crescents appearing in the soyonbo and on other
Mongolian flags.
Ned Smith, 16 March 2005

The yellow flag with the huge U on it is the sign of the "Asiatic
Cavalry Division" led by Baron Roman Federovitch Ungern Sternberg.
This was the last unit of the anti-Bolshevik White Army.
In February 1921 the division took the town of Urga (now Oulan-Bator = town of red heroes). Ungern was seen by inhabitants as the god of war
and the reincarnation of Genghis Khan.
The flag specification is gold with a black horse shoe in the center.
The U or horse shoe stands for Ungern, leader of the state. He was
executed by the Communists on 17 September 1921.
The comic book by Hugo Pratt uses historical facts.
Zachary Fois, 22 November 2006

Flag(s) might have been used by Baron Ungern-Sternberg and the Asian Cavalry
Division during the Baron's 1921 occupation of Mongolia:
The book "The Bloody White Baron" by James Palmer (New York:Basic Books; 2009)
makes a several short mentions of flags used during the Ungern-Sternberg
invasion and occupation of Outer Mongolia.
(Page 129)- "The banners under which the army rode were nearly as varied as the
soldiers themselves but two symbols were particularly important. One was a curly
capital M with II below it and a crown above. This stood for Michael II, the
missing but, Ungern hoped, future monarch of Russia" [This was the Grand Duke
Michael, younger brother of the last Tsar, Nicholas II. Unknown to
Ungern-Sternberg Michael had already been murdered by the Bolsheviks]... "One
surviving banner shows this symbol on one side and the face of Christ on the
other; the colour, however, was Buddhist Yellow, thus appealing to both aspects
of Ungern's beliefs. The other popular symbol was the swastika, often matched
with the Mongolian soyombo. This was, of course, an old and valued Buddhist
motif, but Ungern would also have been aware of its anti-Semitic interpretation,
as would most of the Whites."
Palmer makes no mention of the supposed flag with a horseshoe which we show- I
can't help wondering if that could have been based on a fleeting view and
misinterpretation of the M above II flags? Of course if so, then the horseshoe
would have to subsequently be inverted to get the image as we show it.
(Page 163) [describing the victory celebration after Ungern-Sternberg drove the
Chinese out of Urga, and restored the Bogd Khan (Holy King), or "Living Buddha",
to power] "In their centre was a horse-drawn wooden pyramid on a cart, from
which a huge flag rose. On it, woven in gold thread, was the soyombo, a national
symbol of Mongolia, created by the first Bogd Gegen." [Bogd Gegen- "Holy Shining
One" was an alternative title for the Bogh Khan. The Bogd in 1921 was the
eighth; the first lived 1635-1723.]
(Page 178-179) [regarding the Mongolian communist forces which defeated
Ungern-Sternberg] "Their first unit, formed on 17 February [1921], consisted of
twenty horsemen riding under two yellow-and-red banners. The red was for
communism, the yellow for Buddhism."
Palmer's book seems well-researched. He lists a large bibliography of sources
consulted, and he documents many of his statements. Unfortunately, he has not
cited sources for the above statements regarding the flags, other than the vague
mention of a surviving flag with the M II symbol.
Ned Smith, 10 August 2010

screenshot from YouTube

screenshot from YouTube

screenshot from YouTube

The flag of the "Mad Baron" is preserved and it can read like "God help us," or "In God We Trust" words.
-- Video 1. http://www.youtube.com/watch?v=...See 0,24 minute: orange flag with "U". 0.08 Blazon Ungern, 1,57 min. true fag.
The simple black flag with the letter "U" in orange background is very Russian look for the letter U is shaped like a horseshoe and a Russian ever place a horseshoe on your home or vehicle to bring luck with the tines down: for Russians a symbol of misery i unfortunately.
-- Video 2. http://www.youtube.com/watch?v=...See min 0,39
-- Video 3. http://www.youtube.com/watch?v=...see 2,38 min: front and back of the 1921 flag with the words about God of which I have spoken.
Authentic flag stored in a museum, probably as a war trophy..
David Montón Farrioli, 5 March 2014

The words are "God (is) with us" (if translated literally, there would be no word "is").
Tomislav Todorovic, 6 March 2014

I think flag with the letter "U" is a mistake. It did not exist.
Monogram "M" on the Ungern banner could be misinterpreted as a horseshoe. Victor Lomantsov, 11 April 2014

Well, that was David Montón Farrioli position as well, it seems, as he
distinguishes between 0,24 minute: orange flag with "U" and 1,57 min.
true flag.

Based on the image at 40s, I expect. The fact that an M-like cypher
upside-down could possibly be interpret as a U doesn't convince me that
that's how the U flag report came into existence. Even less so since the
poster of that video, Mad Monarchist, shows that same emblem right side
up on every page of his blog ().
If such a mistake ever took place, I would expect it was further in the
past.
Peter Hans van den Muijzenberg, 10 May 2014

This flag was adopted 26 November 1924 when the People's Republic was proclaimed. William Crampton's The World of Flags shows a picture of this flag with some diferences. The first soyonbo was used in blue on the yellow flag of 1911, and was more complex.Mark Sensen, 24 April 1996

The ratio as drawn in Flaggenbuch [neu92] is about 5:9~, but there is no indication if
that was somehow regulated.Zeljko Heimer, 29 June 2002

In Flaggenbuch 1932 [neu32] the lower element is less wild; more like a fan or an abstract flower.Peter Hans van den Muijzenberg, 7 July 2002

The lower element of 'soyombo' (variant 1924) is flowers of lotus, symbol of victory. I read that lotus was added to 'soyombo' after the victory of Mongolian and soviet troops at Khalkhin-Gol (1939), but I am not sure.Victor Lomantsov, 22 April 2001

This flag was adopted on 26 November 1924 and abolished on 30 June 1940. Source: William Crampton, World of Flags.Jaume Ollé, September 1997

The illustrated flag handbook - Maria Costantino, 2001, has this flag as
being adopted 12 February 1912, and has:

"At the top is a fire symbol, representing the family hearth and the
Mongolian people, its three flames signifying the past, present, and
future. Below this are symbols of the sun and moon, referring to Mongolia's
Shamanistic traditions.Two triangles represent arrows or spears poiting to
the ground, denoting "death to enemies," while two rectangles represent a
fortress and symbolize Mongolia's strength as a nation. In Mongolian
symbolism, the yiin-yang circle that appears within the emblem represents a
fish, signifying reason and wisdom (becasue fish nver close their eyes).
This emblem was placed centrally on the flag between 1924 and 1940, being
moved to the hoist during the period of communist rule, when a socialist
star, along with a central blue stripe, was added. The star was removed in
1992."

Peter Hans van den Muijzenberg, 7 July 2002

"Soyombo", the symbol on Mongolian flag was always yellow since
1924. In the wed site it was shown blue. It is called "Golden
Soyombo".Mash O.Sarlagtay, 24 April 2006

I visited Mongolia two times to research their flags and bought Mongolan flag books at a few museums and book stores.
I could not find several historical flag images already reported from Europe such as ... "mn-1924" red flag with blue soyombo in the center
...
It is amazing to me. Mongolian flags design during that time were much more complicated.
Likewise they had national emblems with complicated design than we thought."
Nozomi Kariyasu, March 2015

Photo of Mongolia Museum display of historic flags of Mongolia 1911-1992:
https://groups.yahoo.com/...The Museum photo does not mention the Red/Blue version listed as 1924-40 by FOTW or the reported 1921
"red flag with yellow ball and crescent flag".
Ben Cahoon, 27 March 2015

Reconstructed image of the Mongolia flag used 1924 - 1930,
made after photo of Mongolia Museum display of historic flags of Mongolia 1911-1992:
https://groups.yahoo.com/...Museum photo varies from flags reported from western sources. My bet is that the early flags were probably not widely used outside government and maybe at the Mongolia embassy in the USSR.
Ben Cahoon, 27 March 2015

Mongolian Constitution 1924: "The state flag is red, with the state emblem [i.e. the soyombo] in the centre."
Brendan Hennessy, March 2015

This looks like a lot of the religious symbolism was removed, but the
symbol itself was retained. This sort of matches with the declaration
that now that the Bogd Khan was dead, there would be no new incarnation
of the Bogd Gegen. They're not changing the government structure itself,
but they're removing the religious aspect.
(This got to be much worse as the Stalinist-like purification especially
sought to remove all traces of Buddhism from the country. It's estimated
that 5% of the population was killed.
Peter Hans van den Muijzenberg, 9 April 2015

Reconstructed image of the reported Mongolia flag in use 1930 - 1940,
made after photo of Mongolia Museum display of historic flags of Mongolia 1911-1992:
https://groups.yahoo.com/...Museum photo varies from flags reported from western sources. My bet is that the early flags were probably not widely used outside government and maybe at the Mongolia embassy in the USSR.
Ben Cahoon, 27 March 2015

from 1938 Atlas

Mongolian flag - photo from the Flagchart in the "Atlas of the Workers` and Peasants' Red Army Commander. 1938"
( full page)
Victor Lomantsov, 1 March 2016

Flaggenbuch 1939 also provides a merchant flag: yellow flag with red saltire and blue soyombo
in the middle. The red saltire is "broken" where the soyombo is
(i.e. is not "seen though" the soyombo, rather the yellow background is).Zeljko Heimer 29 June 2003

"Soyombo" was incorrectly drawn in the merchant flag, (indeed, I
did not know we have a merchant flag). It is also blue. That is most
likely be a yellow "soyombo" on blue shield.Mash O.Sarlagtay, 24 April 2006

I visited Mongolia two times to research their flags and bought Mongolan flag books at a few museums and book stores.
I could not find several historical flag images already reported from Europe such as ... "mn~1924" yellow merchant flag from
FLAGGENBUCH. It is amazing to me. Mongolian flags design during that time were much more complicated.
Likewise they had national emblems with complicated design than we thought.
Nozomi Kariyasu, March 2015

Barraclough 1981, has it that Mongolia was recognised formally on
5 January 1946, and that it at that time had a red flag with blue
soyombo, and a red merchant ensign with yellow saltire and blue soyombo
(which is the opposite of Flaggenbuch). Added is the note that blue is
the Mongol national colour. Peter Hans van den Muijzenberg, 9 April 2015

Reconstructed image of the Mongolia flag in use 1940 - 1949 ?,
made after photo of Mongolia Museum display of historic flags of Mongolia 1911-1992:
https://groups.yahoo.com/...Museum photo varies from flags reported from western sources. My bet is that the early flags were probably not widely used outside government and maybe at the Mongolia embassy in the USSR.
Ben Cahoon, 27 March 2015

Mongolian Constitution 1940: ""The flag of the Mongol People's Republic consists of a red cloth with the State Emblem [i.e. the rider] depicted in the centre, and with the inscription on either side 'Mongol People's Republic"
Brendan Hennessy, March 2015

The rider at that time being a herdsman galloping towards the sun, I
think, with pastoral animal heads around the scene. I don't know whether
the State Emblem is the same thing we call the seal, though.
Peter Hans van den Muijzenberg, 9 April 2015

"In the stripe along the hoist stands a golden star, the symbol of the
communist party, with below that the old traditional symbol of Mongolia,
the /soyonobo/ ... . The two symbols together represent the ideology of
communism, gand in hand with the traditional way of life and thinking of
Mongolia. This flag was officially adopted in 1940."

And:

"The 'badge' on the flag of Mongolia combines the star of communism with the
traditional Soyonobo symbol. The flame means progress, the sun and moon an
everlasting existence, the small triangles a warning for the enemy, the
bars honesty and strength, the ying and yang emblem vigilance."
(translated by P.H.v.d.Muijzenberg)

Peter Hans van den Muijzenberg, 7 July 2002

Politikens Flagbook [pik00] has:

"The current state flag has replaced the red flag of the revolution in 1940.
Until 12.2.1992 the star of communism sat over the /soyonbo/ . ..." (translated by P.H.v.d.Muijzenberg)

The explanation of the symbolism has the three flame tongues for past,
present, and future, the sun and moon for the predecessors of the Mogolians, the horizontal bars vigilance required from everyone in society,
the "fishes" for vigilance, as fishes never sleep, and the upright columns for the proverb "Two friends are stonger then stone. (Also, it neglects to explain the triangles.)Peter Hans van den Muijzenberg, 7 July 2002

We know the "1960" flag was already adopted in 1945. The Mongolian Wikipedia seems to say it was chosen on or around June 10?
and 1960 July 6 confirmed in constitution.
Ben Cahoon, 27 March 2015

Mongolian Constitution 1960: "The state flag of the Mongolian People's Republic shall proceed from the state arms and shall consist of a red and blue cloth, wherein a sky-blue strip occupies one-third of the middle of the flag, and the two other parts located on both sides are red. In the upper portion of the red cloth affixed at the staff shall be a gold five-pointed star under which is the mark 'soëmbo,' also gold. The proportion of the width to length shall be 1:2"
Brendan Hennessy, March 2015